The selective removal of a portion of a thin film during the microfabrication of an electronic device is routinely performed in a photolithographic process. Typically, the resins present in these thin films exhibit photo-patternable qualities. Thin films may also be applied to the surface of an electronic device that can be developed as a dielectric material for protective purposes. Although the thin films in these two applications are applied to the same or similar surfaces, their properties and purpose are substantially different.
An example of a photo-curable resin composition is disclosed in Japanese Kokai No. H04-170547 in which the resin composition is used as a protective layer on color filters. The resin composition consists of a photo-polymerization compound having an unsaturated double bond and a carboxyl group, a photo-polymerization starting agent, an epoxy containing compound, and a (meth)acrylate compound including a silicon atom in a predetermined position. A paint film comprising the resin composition exhibits adhesiveness, photosensitivity to UV exposure, and excellent flatness.
Japanese Kokai No. H09-235358 also describes a photo-curable epoxy resin composition that is capable of being cured over a short-time period. The epoxy resin composition comprises an epoxy resin that has two or more 1,2-epoxy groups, a rubbery elastic resin liquid, an inorganic filler, and a group VIb element onium salt. The onium salt is capable of receiving UV light to release a Lewis acid onium salt.
Japanese Kokai No. H08-160623 discloses a positive-type resist material that is sensitive to high energy beams and far ultraviolet rays. This resist material is capable of forming a fine pattern with a high aspect ratio that is resistant to oxygen plasma etching. The resist material is developed in an alkali aqueous solution containing an acid generating agent and a silicone polymer having both a —CH2CH2COOH moiety and a —CH2CH2COOR moiety, where R is a t-butyl group, a t-butoxy carbonyl methyl group, a trimethyl silyl group, or a tetrahydropyranyl group.
The ability of resin to be both photo-definable and developable as a dielectric material would be desirable. The properties exhibited by such a resin, for example, low dielectric constant, high light transmittance, and excellent thermal stability, would be beneficial when the resin is used in a variety of applications.